Nanosized yolk-shell Fe3O4[at]Zr(OH) x spheres for efficient removal of Pb(II) from aqueous solution

• Published in: Journal of hazardous materials Vol. 309; pp. 1 - 9
• Main Authors: Pan, Shunlong, Li, Jiansheng, Wan, Gaojie, Liu, Chao, Fan, Wenhong, Wang, Lianjun
• Format: Journal Article
• Language: English
• Published: 01.05.2016
• Subjects: Adsorbents; Adsorption; Holes; Isotherms; Nanospheres; Scanning transmission electron microscopy; Surface chemistry; X-ray photoelectron spectroscopy
• ISSN: 0304-3894
• DOI: 10.1016/j.jhazmat.2016.02.003

In this work, Fe3O4[at]Zr(OH) x yolk-shell nanospheres (YSNs) were synthesized via a two-step process and further examined as adsorbents for the removal of Pb(II). To understand the hollow structure on the adsorption properties of Pb(II), another adsorbent without hollow cavities, i.e., Fe3O4[at]SiO2[at]Zr(OH) x core-shell nanospheres (CSNs), was also prepared for comparison. The adsorption results showed that Fe3O4[at]Zr(OH) x YSNs exhibited 41.6% higher Pb(II) adsorption capacity as compared to that of Fe3O4[at]SiO2[at]Zr(OH) x CSNs. The isotherm was well fitted to Langmuir adsorption model with q max value of 310.8mg/g after normalized by the weight of Zr in Fe3O4[at]Zr(OH) x YSNs. Scanning transmission electron microscopy (STEM) mapping results revealed that the existence of cavities between Fe3O4 cores and Zr(OH) x shells is responsible for the improved adsorption performance. XPS analysis indicated the surface hydroxyl groups played a key role in the Pb(II) adsorption. The removal efficiency of Pb(II) was maintained above 90% in five consecutive adsorption-desorption cycles.